Re: Real-time category

[Jeff Larson <Jeffrey.Larson@Sun.COM>]

 > "PC/Mac software doesn't get to be in the real-time category, cause if
 > it runs on MacOS or Windows, it can't honestly be called real-time! It
 > can still be very powerful stuff, though...."
 >
 > I don't understand the quote, its obviously wrong, I do realtime
 > looping since more than a decade with software running on various
 > OSes, mostly OS X now. There must be a debate about it...

Hmm no, there has never been a "hardware" vs. "software" debate here :-)

In operating systems, the term "real time" means that it follows some
very strict rules, home computer operating systems are not technically
real-time.  Exactly what real-time means is complicated, but basically
the OS is designed guarantee that certain operations such as servicing
an audio or MIDI interrupt happen within a small and consistent period
of time.

It is certainly debatable whether this distinction is important in
modern PC operating systems.  There are techniques that can be used to
partially solve the problems and many people find them acceptable.
For all practical purposes "buffering" solves the problem of
inconsistent servicing of audio interrupts but buffering adds
"latency" which will be much higher on a PC OS than a real-time OS.
Some people cannot tolerate this higher latency, others can.

Buffering can't solve everything, if you are running an audio
application at the same time as you are defragmenting your hard disk
or playing Half-Life then you will have "glitches" no matter how large
the buffer is.  But these situations can usually be avoided during a
performance.

To me there isn't really a debate.  Both dedicated hardware and
general purpose computers have strengths and weaknesses.  It is a
personal choice which strengths you prefer and which weaknesses you
are willing to accept.  Unlike politics, neither side is necessarily
"right" :-)

Jeff